SOURCES:

Columbine by Dave Cullen

New York Times

Psychology Today

https://www.washingtonpost.com/local/the-twisted-minds-of-school-shooters-and-the-anguished-man-who-studies-them/2016/06/30/44987378-2e4e-11e6-9b37-42985f6a265c_story.html

https://www.westword.com/news/anne-marie-hochhalter-moving-letter-to-dylan-klebolds-mom-about-columbine-7602320

https://metro.co.uk/2019/04/20/remembering-the-13-victims-of-columbine-high-school-massacre-20-years-on-9228117/

History.com

You Tube

ABC News

American Tragedy Documentary 

Deadline